Apparatus for making a flexible closure

ABSTRACT

A mechanism and method for attaching strips such as those having an interlocking profile thereon to a laminated sheet of plastic wherein the sheet is preheated by passing it over a heated roller and then passed over a heated joining roll having a nip formed with a pressure roll and feeding a freshly extruded hot strip into the nip and onto the sheet and thereafter applying localized cooling after the strip.

oguchi Jan. 22, 1974 [54] APPATUS FOR MAKING A FLEXIBLE 3,532,57110/1970 Ausnit 156/500 CLQSURE 3,075,868 l/l963 Long 156/282 v 3,575,7624/1971 Goehring et al. 156/244 Inventor: fi l-"3: ipg l fie h f gpl bl3,543,379 12/1970 Naito 156/91 21 ew o lmac 1 g. o. 3 Tokyo JapanPrimary Examiner-Alfred L. Leavitt [22] Filed: Sept. 7, 1971 AssistantExaminer-Caleb Weston [2]] A l N 178 086 Attorney, Agent, orFirm-Carlton Hill et al.

pp o.:

57 ABSTRACT 44, 00 [52] U S Cl 156/498 156/2 156/5 A mechanism andmethod for attaching strips such as [51] Int. Cl B32b 31/30 h h l n h l[58] Field of Search 1515/91, 92, 244, 282, 322, t mg P r a nated sheetof plastlc wherem the sheet 15 preheated 156/498, 499, 500, 150/3 bypassmg 1t over a heated roller and then passed over [561 Cited iuiifiifl iii igifli iiifhi litffiflifi 132335155; UNITED sTTEs PATENTS thenip and onto the sheet and thereafter applying lo- 1;: 33218:; calizedCooling ft the strip 3,462,332 8/1969 Goto 156/244 14 Claims, 3 DrawingFigures PATENTED 3.787. 269

INVENTOR. 75x4 5/ /l 0 sac/w @}%TTORNE Y8 APPARATUS FOR MAKING AFLEXIBLE CLOSURE BACKGROUND OF THE INVENTION This invention relates to amethod and apparatus to join plastic strips of various interlockingfastener means to laminated film continuously and automatically so as toproduce therefrom reclosable bags made from said laminated film andfastener strips attached thereto. Conventional reclosable plastic bagsfeaturing various types of plastic fasteners have hereto been used asone of the necessities of modern living because they are, as indicated,reclosable and also very convenient. However, the above mentionedconventional plastic fastener bag consists of a simple combination offastener means and bag bodies, both of which are formed integrally andat the same time of a single plastic or resin material, for example,polyethylene or polypropelene, because of the requirements of themanufacturing method.

Such reclosable bags formed of a single material are suitably used forthe purpose of getting their contents in and out or preserving themtherein, but since their material is made from a single sheet and is notabsolutely airtight, their use as bags for such goods as medicines orfoods, the quality of which might be affected by air or moisture, is notappropriate.

Therefore, in the case of packaging goods where it is necessary toprotect their quality, it is desirable that bag bodies be formed of moreair impervious laminate films, which may be formed of a lamination ofcellophane and/or paper and/or aluminum, etc. together with a resin filmsuch as polyethelene or other plastic. It is nearly impossible in viewof the existing production equipment and its operation to producelaminated films and fastener means by the method of extruding both thelaminated film and the fastener means at the same time, as in themanufacturing of reclosable bags formed of a single material. Further,the method of laminating another different film on the already formedfastener film also is not desirable because when both are attachedtogether the pressure added thereon by the heating and pressure rollscauses changes in the structural form of the fastener means to takeplace. Therefore, the method of joining fastener means on to laminatedfilm formed separately, is the most appropriate, in which case there aretwo methods of proceeding: These are: the use of a binding agent or themethod of joining by fusion through heating. The method of joiningfastener strips, which keep the fusing heat required for joining, byattaching them soon after they are extruded, to the already separatelyformed laminated film, which itself is reheated, has a weak point inthat the completed bags lose value as commercial products, due to theunequal cooling that results from the difference of thickness betweenthe fastener profiles and their web portions and the film to which theyare attached, and which produces shrink marks and/or wrinkles on thefilm near and adjacent the fastener strips. In the case of laminatedplastic and aluminum film it also very often happens that the fusing andcombining of the film with the fastener is not accomplished perfectlybecause of the difference between the resin material and the aluminum intheir capability of maintaining heat, from the time of heating to thepoint of joining. On account of various difficulties in manufacturingmethods full barrier bags consisting of fastener strips attached tolaminated film have never been developed up to now, though there aremany bags without fastener means made from such laminated film.

In view of the above problems, it is an object of this invention toprovide the methods and apparatus to fuse and join the webs of thefastener strips to laminated films continuously and automatically.

A feature of this invention is to prevent the laminated film fromshrinking and to keep the construction of the fastener strips withinrequired sizes.

This is done by providing at an appropriate place a heating roll, whichgives adequate heat to the laminated film and by then joining thefastener strips which have just been extruded and still retainsufficient extrusion heat, to the laminated film, heated to a fusiontemperature by the said heating roll, and thereafter by maintaining thedesired differential cooling by emphasizing the cooling of the fastenerstrips, and their attached webs, which due to their thickness wouldnormally take longer to cool. An embodiment of this invention will nowbe described, by way of example, with reference to the accompanyingdrawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side elevational viewof a mechanism constructed and operating in accordance with the presentinvention;

FIG. 2 is a schematic sectional view showing a laminated sheet withfastener strips attached, as a product produced in accordance with thepresent invention; and

FIG. 3 is a schematic sectional view of a bag formed from the sheet ofFIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a machine body 1containing therein an apparatus according to this invention, which isattached to a base B. 2 is an apparatus for the unwinding of a roll offilm and also fixed to the base B. This apparatus for unwinding a rollof film 2 has a main shaft 3 which can be revolved by an electric motor5 and the said main shaft 3 is provided with an arm, which is not shownin this drawing, with both ends of this arm being further provided withrevolving frames 3a and 3b for winding up the laminated film roll 4which is separately made.

A tension control roll 6 provided above the apparatus for unwinding theroll of film 2, gives adequate tension to the film moving through, afterunwinding. Film F passing through this tension control roll 6 is pulledout by the rotation of a take-up roll 7 installed in the machine bodyFilm F is then transferred from the said take-up roll to the heatingchamber.

In this heating chamber, the heating roll 11 is installed in the machinebody 1, and rotated by a motor 8, via a transmitting axis 9 and a chain10. The said heating roll 11 rotates and is equipped with a heatingsystem that will allow it to be heated to a desired temperature.Therefore, Film F after being transferred from the above mentionedtake-up roll 7 is put on the heating roll Ill and isheated to thedesired temperature by contact with the heating roll 11. Now, the heatedfilm F is transferred to a joining roll 13 and is joined with fastenerstrips C. Further, the above mentioned joining roll 13 is also providedwith a heating source and if the film is not fully heated by the heatingroll or loses some of its heat while it is being transferred to thejoining roll, from the heating roll, the film can be re heated to thedesired temperature by said joining roll 13.

A weakened tear line is formed in the laminated film by thinning same orby perforating it with a cutter 12 stationed between the above mentionedheating roll 11 and the joining roll 13. Below the joining roll 13 anextruder 16 that is movable back and forth against the surface of saidroll, is provided, and fastener strips C are extruded therefrom andjoined with film F passing over said joining roll 13 at said joiningroll. Thus, the film F is fused with the fastener strips by the joiningroll 13 and is then transported over several guide rolls G provided inthe machine body 1 to a winding station where it is wound up.

Further, while being transported over the guide rolls G, the portion ofthe film F that joins the fastener C is strongly cooled by cool airblown out of cooling devices 17 and 18 located near the joining roll.The said cool air is supplied to cooling devices 17 and 18 through aduct 20 from air conditioning equipment 19 provided in the machine body1.

The drawing also shows a handle which moves a press roll 14, a roll 21that controls the course by which film F is transferred, and a take-uproll 22. Next, the operation of the above mentioned structure isexplained as follows:

The above film having been pulled out of the apparatus 2 used forunwinding a roll of film, is heated before it is combined with thefastener strip C by a joining roll 13. In the case where both the filmand the fastener strips are made from the same resin material, it is notnecessary that both of them are heated by the heating roll 1 1 becauseboth of them can be perfectly fused and combined with each other bysimultaneous extrusion.

But, in the case of laminated film it is impossible, as mentionedpreviously to extrude integrally at the same time both the film and thefastener strips. When the fastener strips are fused and combinedcontinuously with the already formed laminated film, which is in cooledcondition, since it was formed long before, the film must be reheated tothe desired temperature by a heating roll 11, as the said film has losta temperature suitable for fusing and this must now be delivered to it.However, when the above mentioned film F is heated an effective methodof handling the film material is required. For example, in order toproduce economically, it is necessary to have fast speeds of filmpassage and of fastener strip extrusion, as well as to make the filmsuitably hot so as to fuse with the fastener strips as quickly aspossible, and accordingly, it is necessary to raise the temperature ofthe rolls 1]. But, some laminated films, for example, polyethelene andcellophane have a little air left between laminations, which will expandwith the heat and create a number of bubbles between the laminations ofthe film. These deteriorate the quality of the film and must beprevented.

Therefore, in order to prevent the surface of the film F from beingdamaged it is necessary to obtain not only the right temperature forjoining the film to the strips, but also a temperature that will preventthe air between the laminations from expanding with heat and maintainingat the same time a rolling speed of the roll that will not impair theefficiency of production.

In some instances, the laminated film needs to be in contact with theheating roll for a longer time, but the rolling speed of the roll shouldnot be decreased or the efficiency of the production will be affected.Also, some film laminations, cannot be combined with the fastener stripsbecause the heat already given to the film is lost before the film canbe transported to the joining roll. Therefore, in order to avoid theabove mentioned problems, joining roll 13 has its own heating source,which provides a secondary heating of said film, and makes up for thedeficiencyin the heating of the heating roll 11, so that film F may bemoved at high speed and may be given a temperature suitable for fusingwith the fastener strips. Especially for those laminated films that havepoor heat conduction and heat preservation, a better and more efficientheating can be delivered to such films by having a first heating byheating roll 11 and a secondary heating by joining roll 13. Thus, Film Fis fused and combined with the fastener strips C at joining roll 13.Through the above mentioned process, though both film and fastener canbe combined with each other perfectly, it is often difficult to obtainthe desired size of fastener that is suitable for the strength of thefilm to which it is being attached. Hence, bags manufactured withoutconsidering this point are not commercially salable. Therefore, the sizeof the fastener is related to the potential strength of the film. Forexample, a bag body made from a laminated film with weak tensionalstrength that has a fastener with a heavy interlocking element is notdesirable, because of the resistance of the fastener from beingseparated when the bag is opened is stronger than the film adjacent thefastener, so that the film is elongated and damaged, and the bag bodiesform is changed.

Therefore, when the film and the fastener are combined, it is necessaryto pay careful attention to the above mentioned matter. In order that abag is provided with the right combination of film and fastener thateliminates the problems that reduce its commercial value, the extruderproducing the fastener strips, or the orifice part thereof, should bemovable up and down and/or back and forth towards the surface of thejoining roll, so that the distance between the opening of said extruderdie plate and the joining roll may be adjustable. The movement isindicated by the arrowed line 16a.

At the same time, it should also be possible to select the locationpoint where the film is attached to the fastener by moving the die plateor the orifice part of the extruder to both the right and the left sideand in parallel to the joining roll, as shown by the arrowed line 16b.Movement in the direction 16c, normal to the axes of the rolls 13 and14, is also possible. Preferably, only the die portion of the extruderunit is movable for adjustment. The film F with the fastener C made bythe above method is then passed through a cooling process. When both thefastener strips and the film F are cooled to the same temperature at thesame rate, uneven shrinking and wrinkles will appear on the surface ofthe film adjacent the fastener and the resultant bags will becomeimperfect products. This is because, in equal cooling, the rate ofcooling is slower in the fastener strip C and around their web portionthan in their laminated film, and is due to the fastener strips C andtheir webs being thicker than the portion of the film to which they areattached. Therefore, in equal cooling the laminated film with its thinplastic layer is cooled at the higher rate than the thick portion of thefastener and its related web and different shrinking takes place betweenthe former and the latter. This results in noticeable shrink marksand/or wrinkles on the surface of the film adjacent the web of thefastener C.

In order to prevent such a situation, it is necessary to cool both thefastener and the film at different rates so as to provide more coolingto one than to the other. Therefore, according to this invention thefollowing cooling equipment is provided:

Partial cooling is carried out, that is to say, cool air is blown onlyagainst the fastener strips C and their web portions by coolingequipment 17 and 18. Accordingly, only the portions of film F where thefastener webs are attached are cooled as they move over the guide rollsG and are thereby kept at almost thesame temperature as the otheradjacent thin portion of the film against which no fastener heat isapplied. Thus, it is possible to prevent shrink marks and wrinkles frombeing created on the film. Thus, also, according to the method andapparatus for this invention, it is now possible to fuse and combinefastener strips, etc. with laminated films continuously, automaticallyand at high speeds, and to mass produce and supply inexpensivereclosable good quality plastic bags made from different laminatebarrier films having a greater range of protection for the productscontained therein, though this was not technically feasible heretofore.Further, since the main structure of this apparatus consists of amechanism which includes in specific combinations a heating roll, aheated joining roll, special cooling equipment and a special method ofmoving the extrusion equipment, economical production of laminatedreclosable bags is now possible. Since the preheating necessary to fuseand combine fasteners to laminated film can now be suitably given tofilm, the said apparatus is applicable to all kinds of laminate films.In addition, the above mentioned special cooling prevents the film towhich the fastener is attached from abnormally shrinking or wrinkling.These are the features of this invention.

FIG. 2 illustrates a sheet 30 of the type made by the mechanism abovedescribed. This is a sheet which can be doubled at its center, or inother words, folded over on itself, and seamed along the edges to form abag with an open bottom 36.. The profile strips are located so that whenthe bag is doubled over, they are within the bag, as shown in FIG. 3.Also attached to the sheet 30 are reinforcing strips 32 and 33 whichhave aligned ribs extending therealong, and these ribs will guide thetear formed in the bag when the top is torn off. In order to use thebag, the top will be torn off to leave flanges so that the interlockingrib and groove elements may be pulled apart.

The film sheet 30 may be formed of thin plastic or may be a laminationhaving several layers. For example, the inner layer 30a may be of thinplastic film and the outer layer 30b may be of foil or paper or othermaterial which provides stiffness or other properties to the bag. Whilethe example of FIGS. 2 and 3 illustrates a sheet with profile strips 31and 34 and also reinforcing strips 32 and 33, it will be understood thatthe mechanism of FIG. 1 may be utilized to apply various types ofstrips, such as profile strips alone.

I claim as my invention:

ll. A mechanism for forming a sheet with shaped profile strip meanslaminated thereon comprising,

i means supplying a continuous sheet of plastic film,

a heated roller over which the film travels,

means for heating the roller,

means for extruding a heated continuous plastic strip having a shapedprofile on the outer surface, said extruder positioned so that theheated strip is ap plied to the heated film on the roller with its innersurface contacting the film.

2. A mechanism for forming a sheet with strip means thereon constructedin accordance with claim 1 and including means for cooling the stripindependently of the sheet after said joining zone.

3. A mechanism for forming a sheet with strip means thereon constructedin accordance with claim I and including first and second sequentialcoolers positioned after said joining zone and arranged to direct a flowof cooling fluid at sequential positions onto said strip independentlyof the sheet.

4. A mechanism for forming a sheet with strip means thereon constructedin accordance with claim 1 and including means for forming a tear linepositioned between the heated roller and said joining zone and forming atear line along the sheet.

5. A mechanism for forming a sheet with strip means thereon constructedin accordance with claim 1 and including cooling means positioned aftersaid joining zone for directing a flow of cooling fluid onto said stripand onto the area of the sheet immediately adjacent the strip.

6. A mechanism for forming a sheet with strip means laminated thereon inaccordance with claim 1 wherein said extruding means includes means forextruding a plurality of heated strips and said strips are applied tothe heated film in said joining zone.

7. A mechanism for forming a sheet with shaped profile strip meansthereon comprising,

means supplying a continuous preformed sheet of plastic film,

means for receiving and heating the preformed sheet a joining roll overwhich the sheet travels,

means for heating said joining roll, and

an extruder for extruding a continuous plastic strip having a shapedprofile on the outer surface in position for feeding the strip onto thesheet on said joining roll with the inner surface engaging the sheet.

8. A mechanism for forming a sheet with strip means thereon inaccordance with claim 7 wherein the structure includes means foradjusting the position of the extruder toward or away from the joiningroll whereby the heat retained within the plastic strip received fromthe extruder is varied when the strip reaches the joining roll.

9. A mechanism for forming a sheet with strip means thereon inaccordance with claim 7 including means for heating the joining roll.

10. A mechanism for forming a sheet with strip means thereon constructedin accordance with claim 7 including means for adjusting the position ofthe extruder die opening relative to the joining roll.

111. A mechanism for forming a sheet with strip meansthereon'constructed in accordance with claim 7 wherein said extruder isadapted for extruding a plurality of continuous plastic strips inposition for feeding the strips onto the sheet at the joining zone onthe roll.

means supplying a continuous sheet of plastic film,

a heated roll over which the film travels,

means for heating said roll,

means for extruding first and second heated continuous plastic stripshaving mating interlocking profiles thereon,

said extruding means positioned so that said profile strips are appliedto the heated film on said heated roll,

and means applying a tear strip means between said profile strips.

1. A mechanism for forming a sheet with shaped profile strip meanslaminated thereon comprising, means supplying a continuous sheet ofplastic film, a heated roller over which the film travels, means forheating the roller, means for extruding a heated continuous plasticstrip having a shaped profile on the outer surface, said extruderpositioned so that the heated strip is applied to the heated film on theroller with its inner surface contacting the film.
 2. A mechanism forforming a sheet with strip means thereon constructed in accordance withclaim 1 and including means for cooling the strip independently of thesheet after said joining zone.
 3. A mechanism for forming a sheet withstrip means thereon constructed in accordance with claim 1 and includingfirst and second sequential coolers positioned after said joining zoneand arranged to direct a flow of cooling fluid at sequential positionsonto said strip independently of the sheet.
 4. A mechanism for forming asheet with strip means thereon constructed in accordance with claim 1and including means for forming a tear line positioned between theheated roller and said joining zone and forming a tear line along thesheet.
 5. A mechanism for forming a sheet with strip means thereonconstructed in accordance with claim 1 and including cooling meanspositioned after said joining zone for directing a flow of cooling fluidonto said strip and onto the area of the sheet immediately adjacent thestrip.
 6. A mechanism for forming a sheet with strip means laminatedthereon in accordance with claim 1 wherein said extruding means includesmeans for extruding a plurality of heated strips and said strips areapplied to the heated film in said joining zone.
 7. A mechanism forforming a sheet with shaped profile strip means thereOn comprising,means supplying a continuous preformed sheet of plastic film, means forreceiving and heating the preformed sheet of film, a joining roll overwhich the sheet travels, means for heating said joining roll, and anextruder for extruding a continuous plastic strip having a shapedprofile on the outer surface in position for feeding the strip onto thesheet on said joining roll with the inner surface engaging the sheet. 8.A mechanism for forming a sheet with strip means thereon in accordancewith claim 7 wherein the structure includes means for adjusting theposition of the extruder toward or away from the joining roll wherebythe heat retained within the plastic strip received from the extruder isvaried when the strip reaches the joining roll.
 9. A mechanism forforming a sheet with strip means thereon in accordance with claim 7including means for heating the joining roll.
 10. A mechanism forforming a sheet with strip means thereon constructed in accordance withclaim 7 including means for adjusting the position of the extruder dieopening relative to the joining roll.
 11. A mechanism for forming asheet with strip means thereon constructed in accordance with claim 7wherein said extruder is adapted for extruding a plurality of continuousplastic strips in position for feeding the strips onto the sheet at thejoining zone on the roll.
 12. A mechanism for forming a sheet with stripmeans thereon constructed in accordance with claim 7 including means foradjusting the position of the extruder relative to the joining roll. 13.A mechanism for forming a sheet with strip means thereon constructed inaccordance with claim 12 wherein the extruder is adjustable in adirection parallel to the axis of the joining roll so that said stripcan be joined to the film at varying distances from the film edges. 14.A mechanism for forming a sheet with strip means laminated thereoncomprising, means supplying a continuous sheet of plastic film, a heatedroll over which the film travels, means for heating said roll, means forextruding first and second heated continuous plastic strips havingmating interlocking profiles thereon, said extruding means positioned sothat said profile strips are applied to the heated film on said heatedroll, and means applying a tear strip means between said profile strips.